In the field of toners for electrophotography, with the progress of electrophotographic systems, it has been demanded to develop toners adaptable for high image quality and high printing speed. Further, it has been required that the toners are in the form of finely divided particles and have various properties such as a low-temperature fusing property and an anti-hot offset property.
To meet the above requirements, from the viewpoint of enhancing a low-temperature fusing property of the toners, various methods have been conventionally developed. For example, there are disclosed a process for producing a toner by using a crystalline polyester as a raw material which includes a neutralization step, an emulsifying step, an aggregating step and a coalescing step (refer to Patent Document 1), a process for producing a toner which includes a step of aggregating resin particles having a core/shell structure in which a difference in glass transition temperature between a resin forming the core and a resin forming the shell is 20° C. or more (refer to Patent Document 2), a process for producing a toner in which after adding a neutralizing agent and an aqueous medium to an organic solvent solution of a crystalline polyester and an amorphous polyester, an alkaline substance is added to the resulting solution to form O/W-type emulsified resin particles, and then the organic solvent is removed from the resulting emulsion to aggregate and coalesce the resin particles (refer to Patent Document 3), a process for producing a toner having a weight-average molecular weight distribution with two or more peaks, which includes a step of forming aggregated particles in a dispersion containing a crystalline resin and an amorphous resin (refer to Patent Document 4), and the like.
Patent Document 1: JP-A 2006-18227
Patent Document 2: JP-A 2007-322953
Patent Document 3: JP-A 2008-33057
Patent Document 4: JP-A 2007-4080